Many transmission systems, for example broadcasting transmission systems, are built according to a public or proprietary standard. Thus, it can be made sure that transmitters and receivers of the transmission system may work together. However, standards evolve, and in order to secure that devices that are built according to a newer version of a standard may communicate with devices that are built according to an earlier version of the standard, the standard has to be designed backward compatible, and the devices have to be built accordingly. For example, after the introduction of color television (TV), black-and-white TV sets were still able to decode a color TV signal and display a black-and-white image.
Also digital TV standards evolve, for example standards of the digital video broadcasting (DVB) family of standards, such as digital video broadcasting satellite (DVB-S), digital video broadcasting cable (DVB-C), digital video broadcasting terrestrial (DVB-T), digital video broadcasting handheld (DVB-H), and/or the like. For example, DVB-T has evolved into second generation DVB-T2. Even though backward compatibility was not a goal for DVB-T2, compatibility requirements that DVB-T receivers do not get confused by a DVB-T2 signal.
Further, digital video broadcasting next generation handheld (DVB-NGH) is based in part on the DVB-T2 system. As with DVB-H, adaptations are made in order to provide for requirements of a battery powered receiver, for example a DVB-NGH receiver in a handheld device like a mobile computer, a mobile telephone, and/or the like. Again, a compatibility requirement is that a DVB-T2 receiver does not get confused by a DVB-NGH transmitter. For this purpose, a data field in a frame or packet may be defined to have only a limited number of possible values for use in DVB-T2. For example, a 4-bit field may have defined only the values “0000”, “0001”, and “0010” in DVB-T2. Other values (for example “0100”) may be marked “for future use”. These other values may then be used in a DVB-NGH system or any other system evolving from DVB-T2. A DVB-T2 receiver may ignore these other values.